package dbLayer;

import java.sql.*;
public class DbConnection {

	//constants used to get access to the database
	//SQL Server
	private static final String  driver = "jdbc:sqlserver://balder.ucn.dk";
	private static final String  databaseName = ";databaseName=dmae0912_8";
	//jdbc:sqlserver://localhost\SQLEXPRESS/Databases/EPS:1357;user=epsingall;password=welkom1;
	//SQL Server
	private static String userName = "; user=dmae0912_8";
	private static String password = ";password=IsAllowed";

	private DatabaseMetaData dma;
	private static Connection con;
	// an instance of the class is generated
	private static DbConnection  instance = null;

	// the constructor is private to ensure that only one object of this class is created
	private DbConnection()
	{
		String url = driver + databaseName + userName + password;
		try{
			//load the driver
			//SQL Server
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
			System.out.println("Load af class ok");

		}
		catch(Exception e){
			System.out.println("Can not find the driver");
			System.out.println(e.getMessage());
		}//end catch
		try{
			//connection to the database

			con = DriverManager.getConnection(url);
			//set auto commit
			con.setAutoCommit(true);
			dma = con.getMetaData(); // get meta data
			System.out.println("Connection to " + dma.getURL());
			System.out.println("Driver " + dma.getDriverName());
			System.out.println("Database product name " + dma.getDatabaseProductName());
		}//end try
		catch(Exception e){
			System.out.println("Problems with the connection to the database");
			System.out.println(e.getMessage());
			System.out.println(url);
		}//end catch
	}//end  constructor

	//closeDb: closes the connection to the database
	public static void closeConnection()
	{
		try{
			con.close();
			System.out.println("The connection is closed");
		}
		catch (Exception e){
			System.out.println("Error trying to close the database " +  e.getMessage());
		}
	}//end closeDB

	public  Connection getDBcon()
	{
		return con;
	}
	//this method is used to get the instance of the connection
	public static DbConnection getInstance()
	{
		if (instance == null)
		{
			instance = new DbConnection();
		}
		return instance;
	}
	public static void startTransaction()
	{ try{
		con.setAutoCommit(false);
	}
	catch(Exception e){
		System.out.println("Failed to start transaction");
		System.out.println(e.getMessage());
	}
	}
	public static void commitTransaction()
	{ try{
		con.setAutoCommit(true);
	}
	catch(Exception e){
		System.out.println("Failed to commit transaction");
		System.out.println(e.getMessage());
	}
	}
	public static void rollbackTransaction()
	{ try{
		con.rollback();
		con.setAutoCommit(true);
	}
	catch(Exception e){
		System.out.println("Failed to rollback transaction");
		System.out.println(e.getMessage());
	}
	}
}//end DbConnection
